SIRT1 and preeclampsia: Compared with patients with mild preeclampsia, serum SIRT1 expression was lower in patients with severe preeclampsia (p < 0.0001), the arterial blood flow velocity peak-to-trough ratio, pulsatility index, and resistance index were higher (p < 0.001; p < 0.0001); and serum SIRT1 expression and uterine artery hemodynamic parameters were closely related to disease severity (p < 0.001; p < 0.0001).